它给出错误作为列表迭代器不可降低

Question

在此处输入图像说明下面代码会导致编译错误，如std :: list list的迭代器无法降低：

std::list<CItem*>::iterator iter1, iter2;
  std::list<CItem*> listc, list3;
  std::vector<CItem*>::iterator iter;

for(iter1 = listc.begin(); iter1 != listc.end(); iter1++)
  {
    for(iter2 = list3.begin(); iter2 != list3.end(); iter2++)
    {
      if((*iter1)->getID() == (*iter2)->getID())
      {
        iter1 = listc.erase(iter1);
        iter1--;               //this line gives error as list iterator not decrementable
        list3.erase(iter2);
        break;
      }
    }
  }